A newly discovered virus may be one of the causes of a potentially fatal kidney disease in pet cats.

Tubulointerstitial nephritis is a disease that inflames the spaces between the kidney tubules, the tubes that carry fluid for filtration inside the organ. Many factors can cause tubulointerstitial nephritis in humans, from infections to autoimmune disorders to certain medications. But in cats, the cause is rarely known.

Now, researchers in Hong Kong believe they've found at least one culprit: a new virus related to measles and mumps dubbed feline morbillivirus. A dog version of this virus causes distemper, which manifests as vomiting, diarrhea, coughing and deadly neurological symptoms.

"All dogs are vaccinated against the canine distemper virus, because the dog morbillivirus can cause very severe disease in dogs with fever, pneumonia, brain infection, immunosuppression and rash," study researcher Kwok-Yung Yuen told LiveScience. "Despite the close relationship between dog, cat and human, no morbillivirus is found in cats yet. And one of top causes of death in cases due to nephritis leading to kidney failure is quite unknown."

Yuen and his colleagues went looking for this elusive cat morbillivirus, figuring that if viruses in this family could infect dogs and humans, they'd likely show up in cats. They were right. Of 457 stray cats from Hong Kong and mainland China tested, 12.3 percent (56 individuals) carried the virus. A total of 27.8 percent had antibodies to the virus, meaning they had been infected at some point in their lives.

The researchers then conducted autopsies and post-mortem exams on 27 deceased stray cats. They found tubulointerstitial nephritis in seven of the 12 stray cats with evidence of feline morbillivirus infection. Of the 15 uninfected cats, only two had kidney damage.

The virus should not pose a threat to human health, Yuen said, but the findings could be important for cats not just in Hong Kong but also the United Kingdom and the United States. Currently, there is no good prevention or treatment for feline tubulointerstitial nephritis, he said. That's bad news for the 22 percent of Hong Kong pet owners who keep cats, and for the estimated 75 million housecats in America.